... M7: Open Star Cluster in Scorpius . ... M7 is one of the most prominent open clusters of stars on the sky. ... Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. ... Ring Nebula Deep Field . ... A familiar sight to sky enthusiasts with even a small telescope, the Ring Nebula (M57) is some 2,000 light-years away in the musical constellation Lyra. ... VdB 152: Reflection Nebula in Cepheus . ... 152...